Embodiments of the present invention generally relate to imaging devices and methods thereof. More specifically, certain embodiments pertain to rotational scanning endoscopes, rotational scanning endoscope systems, and rotational scanning endoscope methods. In certain embodiments, the rotational scanning endoscope may be a portable and/or low-cost anal canal scanner that can be used, for example, to screen for anal cancer.
Anal cancer is a malignancy of the epithelium of the anal canal. As a malignancy that is associated with human papilloma virus (HPV) infection, the incidence of anal canal cancer has increased markedly over the last two decades. Although screening for anal cancer results in early detection, screening of at-risk populations has not been widely adopted. The current gold standard for anal cancer screening is high resolution anoscopy, a technique adapted from standard cervical examination protocols. In brief, the procedure is conducted as follows: 3-5% acetic acid is applied using soaked gauze into the anal canal for at least one minute. The gauze is removed and a clear plastic anoscope is passed into the anal canal to retract soft tissues away and to allow the anal mucosa to be evaluated. The colposcope is positioned and used to identify abnormal areas delineated by acetic acid and labeled as “acetowhite” areas. These areas are biopsied to obtain a histological confirmation of the abnormality. A handwritten map and photographs of abnormal areas document the location, appearance, and clinical impression of the biopsied areas.
Although high resolution anoscopy is the current standard examination procedure used to screen for anal cancer, this technique has significant limitations. For example, a conventional colposcope (e.g. Olympus OCS-3) used in this procedure has an adjustable magnification in the range of 3×-17× with a field of view from 13-84 mm. The geometry of the anal canal only allows a conventional colposcope to view small areas of the anal canal at any given time. To complete the entire examination, this colposcope would have to be moved and refocused multiple times. In addition, the ability to identify abnormal tissue from the normal tissue is highly dependent on the skill level of the practitioner and the number of biopsies taken during examination. Moreover, the typical anoscopy exam procedure is charted manually. Also, digital photographs of areas of concern are highly desirable for serial follow-up but are logistically difficult to implement with the conventional procedures. Taken together, the entire conventional procedure is time consuming with an average of more than 30 minutes per exam, requires multiple steps in its set up and execution, depends on the skill set of the provider to identify abnormal areas requiring biopsies, and demands high levels of histopathologic resources for support. A simpler, cheaper, and better alternative for imaging the anal canal for screening purposes is needed.